In Novatron's long history,thousands and thousands of products have been manufactured and sold to happy customers. Many of these products are still in use, some on a daily basis. We still support all of them. There have been Novatron bare tube heads that used modeling lamps with a bayonet base. The 4107 is the replacement part for those heads. The 4107 is the replacement modeling lamp for the M150. We are pleased to be here for one of the largest user bases of any A/C flash lighting product made in North America.